Persistent mold release.

[sockwithaticket]

I have some resin components from a couple of different sources (including FW) where after 2 baths (using washing up liquid) and two scrubbings with a toothbrush and soap they are still really shiny and feel a little waxy to the touch. To test whether they're ready I slapped some imperial primer on a couple of pieces and it contracted in on itself like when you've thinned paint to far and it's mostly just water. When what remained dried, it rubbed straight off.

 

So, how do you deal with persistent mold release?

[Ironwulf]

Have you tried giving the pieces a light sanding with some VERY fine sandpaper? That usually does the trick for me, giving the primer something to grab onto.

 

Of course, be careful not to obliterate any detail...

[sockwithaticket]

Thanks for the quick reply. I don't actually own sandpaper of any type and I'm not exactly experienced with it. Could you elaborate on the very fine aspect of the sandpaper? Is there a universal grading system of any kind?

[Azatoth]

Normaly it comes in different grains/cm or inch.

Finest I know is around 1200, on sheets, which you can cut to your needs (to reach different spots).

[Ironwulf]

Normaly it comes in different grains/cm or inch.

Finest I know is around 1200, on sheets, which you can cut to your needs (to reach different spots).

 

 

Right. At least in the U.S., sandpaper grades go from high to low numbers. HIGH numbers (1200) which are FINE grit, suitable for detailed work; but LOW numbers (100, 80, etc.) are COURSE grit, and not very suitable for hobby work.

[Subtle Discord]

As mentioned, you'll look for the 'grit' of the sandpaper - how many particles of grit per inch. When you get up to 1200, it's practically paper-like in how smooth it is, and will do nothing but polish the surface. 600'ish will be a good balance to lightly smooth a surface while barely removing any material. Drop down to 250-400'ish and you'll have a paper that can really remove material, but still leave a clean surface ready for a 600+ finishing. Anything lower is reserved for really rough jobs.

 

Sandpaper is you best bet for very broad flat places, but it's not going to help much on anything with detail. In that case I would use a soft brass and/or steel brush to give the model a light buffing. They can get into nooks-and-crannies, give the surface just enough texture so primer can 'bite', and won't harm even fine details - as long as you keep a light hand.

 

Finally, if it's really bad to the point that the primer just flakes off, even after a buff, I would consider talking to the supplier. A replacement seems in order, or at the very least the manufacturer should be made aware of the short-coming.

[EmbattledSoul]

a vigorous scrubbing with something like comet may do the trick as well since its rather coarse.

[sockwithaticket]

Great, thanks guys! I'll see about getting to a hardware store to enact your advice.

 

The majority of the pieces I'm having trouble with are bases and specifically some relatively large flat surfaces on them so hopefully the sand paper will suffice.

[MordentHex]

Have you tried boiling the resin in coke? thats what i normally do and it works like a charm.

[Darklighter]

Washing up liquid will NOT remove mould release, you need an abrasive cleaner and a tooth brush like object to scrub it off with. Non-abrasive cleaners are just to gentle to do the job correctly.

 

Have fun and happy modeling. :D

[appiah4]

I soak in a tub of water and oven cleaner mix (Mr. Muscle) and scrub a few times.

 

I find hand soaps don't work too well with removing release agents.

[GumbaFish]

I've soaked things in simple green mixed into some warm water, then give them a good scrub and finally rinse with water to get any simple green off. Also as mentioned for flat surfaces I gave it a very light sanding with very fine grit wet/dry sandpaper ( forget what grit) but I got it at an automotive store and you would use it inbetween finish coats of a car paintjob so it is only mildy abrasive. This helped give the primer some tooth to stick on to later on.

[GhostLegion]

for any forgeworld or other resin type models im a big fan of a 3 step prep:

 

1) soaking/rinse/light toothbrush (soft) scrub using diet coke... (though sometimes i let the larger pieces soak til the coke goes flat... damn titans)

2) light toothbrush scrub using undiluted simple green (or comparable product)

3) lukewarm water rinse

 

After this i typically have no problems with release agents screwing up my paint work. however, there are the rare cases when a spot is missed (emperor dragon armpits for instance). in this case, I will typically blend a paint into white glue and apply to that spot. after this, no further problems...

[Master of fact]

good scrub in liquid hot soapy water then dry, then a spray of purity seal never any problems after that method

[striker8]

AS has been said you need to scrub a bit and if using soap it may take a couple of times. I give resin a scrub but use alcohol as a solvent.

[Bannus]

Just this:

 

Easy-Off Oven Cleaner